Integrated optic/nanofluidic detection device with plasmonic readout

Abstract

Integrated lab-on-a-chip devices provide the promise of many benefits in many application areas. A low noise, high resolution, high sensitivity integrated optical microfluidic device would not only improve the capabilities of existing procedures but also enable new applications. This thesis presents an architecture and fabrication process for such a device. Previously, the possibilities for such integrated systems were limited by existing fabrication technologies. An integrated fabrication process including glass nanofluidics, diffused waveguides and metal structures was developed. To enable this process a voltage-assisted polymer bond procedure was developed. This bond process enables high strength, robust, optically clear, low temperature bonding of glass - a capability that was not possible before. Bond strength was compared with a glass-to-glass anodic type bond using various materials and a polymer bond using two polymers: Cytop and PMMA. Bond strength was far superior to standard polymer bonding procedures. Design considerations to minimize background noise are presented, analyzed and implemented. Using Cytop as an index-matched polymer layer reduces scattered light in the device. Plasmonic devices driven via evanescent fields were designed, simulated, fabricated, and tested in isolation as well as in the integrated system. A sample device was made to demonstrate applicability of this process to direct linear analysis of DNA. The device was shown to provide enhanced and confined electromagnetic excitation as well as the capability to excite submicron particles. A demonstrated excitation spot of 200nm is the best we have seen in this type of device. Further work is suggested that can improve this resolution further.